This invention relates to control of data backup by a computer. In particular, the technique disclosed herein relates to lowering of the risk of a failure in restoration of necessary data due to the loss, by deletion, of normal backup data.
Backup software executes backup according to a backup policy created in advance by a system administrator.
A backup policy specifies a backup schedule, the original data location, backup destination storage, a backup data retention period, and the like.
The backup software makes a copy of original data and stores the copy as backup data in the backup destination storage at a backup timing defined in the backup schedule.
Since the backup destination storage has a limited capacity, the backup software deletes backup data that has passed its retention period (a time period in which backup data is kept) before storing new backup data in the backup destination storage. For example, in the case where a backup is taken daily, a week-old backup data may be deleted each time backup is executed.
A technique of predicting a backup result before backup is executed has been disclosed (see JP 2004-206611 A). According to JP 2004-206611 A, whether or not backup can be completed within a given period of time is judged before backup is executed, and a warning is issued when it is judged that backup is not going to be finished within the time limit.
Specifically, in JP 2004-206611 A, a history is kept which records the amount of data backed up and a time required for the backup, and a time required for the next backup is predicted based on the history. In the case where the predicted time exceeds a given threshold, a warning is issued. A user can tune the backup system according to the warning.